AVO 8 Circuits & Parts Lists - UK Vintage Radio Repair and Restoration Discussion Forum

Billy T · 29th Sep 2008, 8:35 am

I am progressively restoring my two AVO 8s, one being a plastic cased Mk V [S/n 87288 8V/4/73] from the Thorn years with the blue "printed wiring" looms, and the other is a much older 8 in the traditional style with the metal plate on top covering the batteries. The latter instrument has no serial number (that I can find) and I don't know what Mark it is or how to establish which it is either.

I started with a good clean up and repairs to physical damage, but on inserting batteries I find that both instruments have electrical defects. The MK V is unstable at the point of zero on the two lower ohms ranges i.e. just as you get the pointer close to zero at full scale, it jumps higher. I suspected worn areas on the pot tracks and temporarily shifted the wipers away from it by inserting series resistors. This improved matters slightly but is not the proper answer. There have been several resistors changed during its life too, and I cannot be sure that they are now the correct values.

The older 8 reads exactly the same on the two lower ohms ranges, which suggests that a shunt is open circuit.

I am hampered by the lack of circuits, the only one I have found on the net is for the "Test Set, Multi Range No. 1" which seems to be a very early model indeed.

Can anybody help me with circuits and parts lists for one or both of these meters please? If so, PM me for an email address or mailing address as required.

Cheers

Billy

russell_w_b · 29th Sep 2008, 10:00 am

Quote:

Originally Posted by Billy T

...The latter instrument has no serial number (that I can find) and I don't know what Mark it is or how to establish which it is either.

Is there not a 'Mark' on the little black circle on the front of the AVO just above the cut-out button? Has your AVO got black knurled bakelite terminals or red-and-black 4mm socket ones? The serial number (indicating the date) is usually on the scale-plate, bottom RHS looking in. If there isn't a serial number there, it may be that the instrument has had a replacement movement fitted.

Quote:

Originally Posted by Billy T

Can anybody help me with circuits and parts lists for one or both of these meters please? If so, PM me for an email address or mailing address as required.

Cheers

Billy

I can scan you a copy of an AVO 8 Mk. III circuit if no-one else beats me to it! I shall put it on the forum as a PDF.

Mark_4CX35000 · 29th Sep 2008, 10:06 am

Manual and circuit diagram for the AVO model 8 MKII can be
found here.

http://www.richardsradios.co.uk/avo8.html

Vicboduk · 29th Sep 2008, 6:57 pm

Hi, I have a copy of the manual and diagram for a model 8 MK V which I can scan for you. For confirmation it's the one with the three range adjusters on the left, the cutout and revmc buttons on the right and connections on all 4 corners.

Vic

SeanMcK · 29th Sep 2008, 9:05 pm

I have full and simplified circuit diagrams for quite a few avo8's and I think one or more of the 9's, there are also parts list for some of them. If you pm me I see what I can sort out. That said with regard to the parts lists, I havent used them in years and was just having a look through them to find the wattage for one resistor that has been cooked and cant find the wattage, maybe my eyes have gone but I am sure that somewhere for some model the wattages were also given.

igranic · 29th Sep 2008, 11:27 pm

Quote:

Originally Posted by Vicboduk

Hi, I have a copy of the manual and diagram for a model 8 MK V which I can scan for you. For confirmation it's the one with the three range adjusters on the left, the cutout and revmc buttons on the right and connections on all 4 corners.

Vic

Vic,

Please would you be very kind and send me a copy of the scanned manual & diagram? I have been searching for this for some time. I will send you a PM.

Edward

Billy T · 30th Sep 2008, 10:06 am

Right.......I've found the serial number, stupid of me to look everywhere but the meter scale

it has HV connectors at the top of the faceplate and the usual inputs at the bottom.

It's late here now so I'll check out the rest of the details in the morning (while you guys sleep) and post the results for you to read over breakfast. Anything's better than reading the news at present.

Picked up an as-new 8 MKIII in immaculate working order complete with mint leather case for about 30 of your pounds this morning and was donated a large 40's Philco console MW/SW radio gram with loctal valves (and in full working order) as a bonus. I wasn't quite sure how I was going to tell Mrs Billy that we had yet another radio coming but she has already made space in the dining room for it so I think it has been adopted into the family sight unseen.

Cheers

Billy

Billy T · 6th Oct 2008, 12:36 am

Gosh it's easy when you know how! The unidentified AVO is an 8 Mk II (the model designation was literally buried beneath 47 years of grime) serial 129737 date of birth 10/61.

My AVO family is now fully identified as follows:

8 Mk II S/n 129737 10/61
9 Mk II S/n 10.037 06/67
8 Mk III S/n 95631 04/69
8 Mk V S/n 87288 04/73

Best of the bunch and the only one not requiring restoration (or even cleaning) is the Mk III that I just bought. It shall serve as the gold standard!

Thanks for all the assistance.

Cheers

Billy

wud-wurks · 29th Oct 2008, 11:51 am

Quote:

Originally Posted by Vicboduk

Hi, I have a copy of the manual and diagram for a model 8 MK V which I can scan for you. For confirmation it's the one with the three range adjusters on the left, the cutout and revmc buttons on the right and connections on all 4 corners.

Vic

I am interested in the circuit diagram of a Model 8 MkV and of a Mk111 if you have it. PM me if it is available as a PDF etc. Much appreciated
wud-wurks

Vicboduk · 29th Oct 2008, 3:33 pm

Hi wud-wurks, you have a PM.

Vic

jim_beacon · 29th Oct 2008, 3:35 pm

you'll find a wealth of AVO data here:

http://www.g1jbg.co.uk/service.htm

Jim.

29th Sep 2008, 8:35 am	#1
Billy T Retired Dormant Member Join Date: Feb 2008 Location: Auckland, New Zealand Posts: 631	AVO 8 Circuits & Parts Lists I am progressively restoring my two AVO 8s, one being a plastic cased Mk V [S/n 87288 8V/4/73] from the Thorn years with the blue "printed wiring" looms, and the other is a much older 8 in the traditional style with the metal plate on top covering the batteries. The latter instrument has no serial number (that I can find) and I don't know what Mark it is or how to establish which it is either. I started with a good clean up and repairs to physical damage, but on inserting batteries I find that both instruments have electrical defects. The MK V is unstable at the point of zero on the two lower ohms ranges i.e. just as you get the pointer close to zero at full scale, it jumps higher. I suspected worn areas on the pot tracks and temporarily shifted the wipers away from it by inserting series resistors. This improved matters slightly but is not the proper answer. There have been several resistors changed during its life too, and I cannot be sure that they are now the correct values. The older 8 reads exactly the same on the two lower ohms ranges, which suggests that a shunt is open circuit. I am hampered by the lack of circuits, the only one I have found on the net is for the "Test Set, Multi Range No. 1" which seems to be a very early model indeed. Can anybody help me with circuits and parts lists for one or both of these meters please? If so, PM me for an email address or mailing address as required. Cheers Billy Last edited by Billy T; 29th Sep 2008 at 8:41 am. Reason: Spellinge misteaks

29th Sep 2008, 10:06 am	#3
Mark_4CX35000 Retired Dormant Member Join Date: Sep 2008 Location: West Yorkshire, UK. Posts: 45	Re: AVO 8 Circuits & Parts Lists Manual and circuit diagram for the AVO model 8 MKII can be found here. http://www.richardsradios.co.uk/avo8.html

29th Sep 2008, 6:57 pm	#4
Vicboduk Hexode Join Date: Aug 2007 Location: S.W. London, UK. Posts: 418	Re: AVO 8 Circuits & Parts Lists Hi, I have a copy of the manual and diagram for a model 8 MK V which I can scan for you. For confirmation it's the one with the three range adjusters on the left, the cutout and revmc buttons on the right and connections on all 4 corners. Vic __________________ It has to be here... I've just put it down!

29th Sep 2008, 9:05 pm	#5
SeanMcK Retired Dormant Member Join Date: Sep 2008 Location: Londonderry, Northern Ireland, UK. Posts: 58	Re: AVO 8 Circuits & Parts Lists I have full and simplified circuit diagrams for quite a few avo8's and I think one or more of the 9's, there are also parts list for some of them. If you pm me I see what I can sort out. That said with regard to the parts lists, I havent used them in years and was just having a look through them to find the wattage for one resistor that has been cooked and cant find the wattage, maybe my eyes have gone but I am sure that somewhere for some model the wattages were also given.

30th Sep 2008, 10:06 am	#7
Billy T Retired Dormant Member Join Date: Feb 2008 Location: Auckland, New Zealand Posts: 631	Re: AVO 8 Circuits & Parts Lists Right.......I've found the serial number, stupid of me to look everywhere but the meter scale it has HV connectors at the top of the faceplate and the usual inputs at the bottom. It's late here now so I'll check out the rest of the details in the morning (while you guys sleep) and post the results for you to read over breakfast. Anything's better than reading the news at present. Picked up an as-new 8 MKIII in immaculate working order complete with mint leather case for about 30 of your pounds this morning and was donated a large 40's Philco console MW/SW radio gram with loctal valves (and in full working order) as a bonus. I wasn't quite sure how I was going to tell Mrs Billy that we had yet another radio coming but she has already made space in the dining room for it so I think it has been adopted into the family sight unseen. Cheers Billy

6th Oct 2008, 12:36 am	#8
Billy T Retired Dormant Member Join Date: Feb 2008 Location: Auckland, New Zealand Posts: 631	Re: AVO 8 Circuits & Parts Lists Gosh it's easy when you know how! The unidentified AVO is an 8 Mk II (the model designation was literally buried beneath 47 years of grime) serial 129737 date of birth 10/61. My AVO family is now fully identified as follows: 8 Mk II S/n 129737 10/61 9 Mk II S/n 10.037 06/67 8 Mk III S/n 95631 04/69 8 Mk V S/n 87288 04/73 Best of the bunch and the only one not requiring restoration (or even cleaning) is the Mk III that I just bought. It shall serve as the gold standard! Thanks for all the assistance. Cheers Billy

29th Oct 2008, 3:33 pm	#10
Vicboduk Hexode Join Date: Aug 2007 Location: S.W. London, UK. Posts: 418	Re: AVO 8 Circuits & Parts Lists Hi wud-wurks, you have a PM. Vic __________________ It has to be here... I've just put it down!

29th Oct 2008, 3:35 pm	#11
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: AVO 8 Circuits & Parts Lists you'll find a wealth of AVO data here: http://www.g1jbg.co.uk/service.htm Jim.